How Nostalgia Works

Have you ever felt nostalgic for the good old days of summer camp? Can you pinpoint what made you feel that way?

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Every now and then, I catch a whiff of summer camp. The smell itself is a mystery (I just cannot put my finger on it; it's maddening), but it's camp, because suddenly I'm 10, and this warmth fills my belly like I'm poised at the edge of a lake, Georgia sun on my back, preparing to dive into still, dark water. I'll be cold until I start swimming, minnows tapping my fingers as I glide toward the rope swing on the far bank, where my friends are waiting.

I close my eyes, smiling, while my heart aches.

It's textbook nostalgia, that bittersweet longing for a certain time in the past. The experience is universal: People of all cultures, locations, backgrounds and ages get nostalgic for idealized versions of their personal histories. Kids as young as 8 can experience it [source: Leardi]. We share similar nostalgia triggers, and we nostalgize (yep, it's a word) about the same types of events.

That's the modern understanding of nostalgia, anyway. When a Swiss doctor coined the term in 1688, it was a different story. Johannes Hofer was observing Swiss soldiers stationed abroad when he noted some of them exhibiting disturbing symptoms: They were depressed, dazed and anxious; they couldn't eat or sleep, had no strength, and suffered fevers and heart palpitations. They avoided social situations and became angry at the drop of a hat. And they just could not stop thinking about home [sources: Hemmings, Daniels].

He called it "nostalgia," from the Greek nostos (return home) and algos (pain). Homesickness. It was, in Hofer's assessment, "a cerebral disease of essentially demonic cause." Animal spirits were vibrating in the soldiers' brains in areas holding "ideas of the Fatherland," making them sick with longing for home [source: Sedikides et al.].

Our understanding of nostalgia has evolved considerably, if not quickly. It was considered a disorder, first a physical and then a mental one, for centuries [source: Routledge]. Seventy-four Union soldiers apparently died from the disease during the American Civil War [source: Matt]. It wasn't until the latter half of the 20th century that a new view began to take hold [source: Sedikides et al.].

Since then, researchers have challenged many long-held beliefs about the nature, and even the definition, of the nostalgic state.

Sentimental and Bittersweet: Defining Nostalgia

While some modern dictionaries offer "homesickness" as a meaning of nostalgia, this feels like a relic. In common use, they just don't mean the same thing: Homesickness is distressing, while nostalgia is kind of nice; homesickness is about place, while nostalgia is about time [sources: Werman, Hirsch].

It's not reminiscence, either. In reminiscence, we recollect. In nostalgia, we feel. Reminiscing may lead to nostalgia, though [source: Leardi].

What exactly is nostalgia, then, besides tough to nail down? It's the complex emotion we sometimes feel when we fondly recall old times — a "sentimental longing or wistful affection for the past" is how the Oxford Dictionary puts it. The nostalgic state is bittersweet, a mixture of the happiness of mentally reliving cherished times and the sadness of knowing they're gone forever — that how we felt in those times is gone forever.

I'll never again know the carefree, unadulterated joy I felt in camp.

Those cherished times are usually social ones, starring us. They probably involve family and friends, took place in childhood or young adulthood and are often at least personally significant, possibly momentous [source: Routledge]. People all over the world experience nostalgia recollecting graduations, weddings, family reunions, birthdays, holiday dinners and vacations with loved ones [sources: Routledge, Tierney]. If movie and TV writers are to be believed, first kisses, senior proms, college road trips and riding bikes with neighborhood kids until dusk are nostalgia fodder, too.

But here's the thing: Our recollections aren't quite accurate. We often unconsciously edit out any bad stuff. (I was actually pretty afraid I was going to swallow one of those minnows.) In this way, the past events and emotions we nostalgize about never really existed [source: Hirsch].

Nostalgia is a complex state, yet it's as common as it gets. Far from a disorder, it seems to be part of the human condition. Most people nostalgize at least once a week [source: Tierney]. Some people are particularly prone to nostalgize, including chronic worriers, who may experience it as an escape from present-day anxiety [source: Tierney]. Nostalgia also peaks in transitional age ranges, notably the teens through 20s (from dependence to independence) and over 50 (from "middle-aged" to "senior") [source: Leardi]. Where am I going? and Where have I been? are straight lines to nostalgia [source: Holak and Havlena].

Songs, smells, photographs and loneliness will trigger nostalgia, too, though some more powerfully than others.

Historical Nostalgia

While most nostalgia is "personal nostalgia," in which people nostalgize about autobiographical memories, some people experience a different type. "Historical nostalgia" refers to longing for a past one hasn't actually experienced, typically a past era (I wish I'd grown up in the '60s. I would have been happier then). Historical nostalgia seems to be a less positive state than personal nostalgia [source: Parry].

Nostalgia and Your Brain

Nostalgia runs high in transitional age ranges: the teens through 20s and over 50 (from "middle-aged" to "senior").

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External triggers for nostalgia are easy to recognize. Looking at old pictures, reminiscing about old times or meeting up with a long-lost friend will all get you to wistful longing.

Less obvious, people seem prone to nostalgize when they're feeling cold [source: Zhou et al.]. We'll get back to that.

As far as sensory triggers go, music is powerful, and songs from adolescence and young adulthood are particularly so — a fact not lost on advertisers, who infuse commercials for everything from cars to yogurt with tracks that their target audiences grew up with [source: Elliot]. Experts theorize that music from this period of our lives is most strongly associated with emotional memories due to properties of the adolescent brain [source: Stern]. The neural activity activated by a song we like, which causes the release of "feel-good chemicals" like dopamine, is activated to a greater extent between the ages of 12 and 22. That extra-intense reaction becomes associated with the events and emotions going on while the song plays. And the emotions going on while the song plays are extra-intense, too, a result of all those "raging hormones" at work in the brain [source: Stern].

Not a lot is known about the brain's role in nostalgia, but it seems to involve connections between stored emotions and memories [source: Ostashevsy]. Researchers have connected music-triggered nostalgia with increased activity in the prefrontal cortex, which is activated when we retrieve autobiographical memories [source: Janata]. Tastes may induce nostalgia in part because the neural pathways carrying information from the taste buds ultimately lead in part to the limbic system [source: Murray]. Scent data lands there, too.

The limbic system, which includes the hippocampus and amygdala, plays a role in the processing and storage of memories (hippocampus), emotions (amygdala) and the "emotional memories" that result when a memory is stored during a highly emotional state [sources: Ostashevsy, Phelps, Levit]. Scent seems to elicit a stronger sense of nostalgia, as well as a more positive and emotional episode, than other triggers [source: Reid]. Might be because the olfactory bulb, which processes smell data from the nose, is right in the limbic system. It has direct links with the amygdala and the hippocampus [source: NBC]. Scents hardly have to travel at all to reach our stored emotional memories.

We typically think of nostalgia triggers along the lines of these types of sensory inputs. Yet one of the most common nostalgia triggers has no sensory component at all.

Bad Moods Trigger Nostalgia?

In a series of studies published in 2006 in the Journal of Personality and Social Psychology, subjects were first asked what leads them most often into nostalgia. The most common answer was not scent, or music, or even reunions with old friends. It was bad moods [source: Wildschut et al.].

Negative feelings appear to be major nostalgia triggers, with loneliness topping the charts [source: Routledge]. It makes sense: Nostalgic memories tend to revolve around positive social experiences — good times with friends, laughing at the "kids table" at Thanksgiving dinner — and in a lonely state, calling on those memories, and yearning to relive them, is a natural response [source: Routledge].

But it seems like almost any dark mood can lead to nostalgia. In one component of that 2006 research, subjects read one of three different news stories. One reported on a tsunami disaster, another on the landing of a space probe, and another on the birth of a polar bear in a zoo. After reading, subjects answered questions assessing their current levels of nostalgia. The subjects who read about the tsunami were the most nostalgic of all the groups [source: Sedikides et al.]. When researchers induced existential angst in a group of subjects (by having them read an essay dealing with the "cosmic insignificance of human life"), those subjects nostalgized more than those who'd read essays without any existential angle [source: Routledge].

Any emotional state that might defy a positive outlook — any "psychological threat" — increases the likelihood of nostalgizing [source: Routledge]. This might seem counterproductive: If we're feeling bad in the present, wouldn't emotionally connecting with a happy past just make us feel worse by contrast? Once the wistfulness subsides, it seems we'd ultimately be left with "I was happier in the past, and I can never go back there."

Surprisingly, it seems to have the opposite effect. Nostalgia, contrary to centuries of common knowledge, appears to be a good thing. A really good thing.

Looking for a Trigger?

Chances are, one of these will get you wistful:

"Casablanca" (1942)

"The Graduate" (1967)

"Annie Hall" (1977)

"Fast Times at Ridgemont High" (1982)

"The Big Chill" (1983)

"Ferris Bueller's Day Off" (1986)

"Stand By Me" (1986)

"The Wonder Years" (1988-1993)

"Say Anything" (1989) (actually, anything with John Cusack)

"Indian Summer" (1993)

"Reality Bites" (1994)

"My So-called Life" (1994-1995)

"Freaks and Geeks" (1999-2000)

"Almost Famous" (2000)

The New Nostalgia

Remembering your prom glory days is OK once in a while. It might even make you happy.

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A visit to the cherished past, especially its idealized version, can offer a fresh perspective on the present. It can remind us we're not alone, that people love us, and that our lives have meaning.

In other words, nostalgia can make us feel better. And it usually does.

Nostalgia, then, can be a coping mechanism — a tool for picking us up when we're feeling lost, or bored, or lonely [sources: Routledge, Routledge].

Or cold. Nostalgia it seems, may have some evolutionary value.

That previously mentioned study linking nostalgia with cold temperatures? It found that chilly subjects were more likely to nostalgize than comfortable ones, yes; but it also found that when chilly people nostalgized, they perceived themselves or their environments as warmer. They also were less susceptible to the pain of extreme cold: When researchers had both nostalgic and non-nostalgic subjects hold their hands in 39 F (4 C) water until they couldn't take it anymore, the nostalgic subjects lasted longer [source: Zhou et al.]. It may just be that wistfully longing for the past helped our ancestors function more effectively in extreme winters [source: Zhou et al.].

It's not all warmth and mood lifts, of course. Nostalgia carries a sense of loss. It can sometimes lead to regret [source: University of Southampton]. But overall, it helps more than it hurts [source: Leibach].

Avoiding comparisons can help maintain that positive balance. A happiness competition between an idealized past and a non-idealized present will seldom turn out well for the present. And two or three episodes of nostalgia per week is plenty [source: Tierney]. Living in the past isn't good for anybody.

An occasional journey to summer camp, then — or senior prom, or the kids' table, or that first college road trip — is perfectly healthy. Heck, it's recommended.

Dwelling on the mysterious trigger that sends you there, possibly less so. (Seriously, what is that smell?) But such is life in the non-idealized present.

The Pathological Variant

Health professionals do still talk about nostalgia in the context of mental illness, particularly depression. This is "pathological nostalgia." Longing for an idealized past can be harmful for people suffering neuroses like chronic worrying, in which nostalgia can trigger an irreconcilable, negative contrast between past and present that becomes a compulsive focus [source: Verplanken]. In conditions of pathological grief, nostalgia can become an obsession that replaces the normal grieving process [sources: Werman, Hirsch].

Author's Note: How Nostalgia Works

Dr. Alan R. Hirsch of the Smell and Taste Treatment and Research Foundation said this about nostalgia: "Nostalgia does not relate to a specific memory, but rather to an emotional state. This idealized emotional state is framed within a past era. Idealized past emotions become displaced onto inanimate objects, sounds, smells and tastes that were experienced concurrently with the emotions." This resonated strongly with me — that nostalgia is really a longing for an emotion, not an event.

It doesn't seem to be the prevailing view, though. So maybe nostalgia means different things to different people. Perhaps this is why, when my husband was helping me brainstorm nostalgia-inducing movies and TV shows for the "Looking for a Trigger?" sidebar, we often disagreed. I tended toward ones with the general theme of "coming of age," while his suggestions were more based on release date — which movies and shows were popular in different time periods. (He doubted millennials would experience nostalgia watching "Stand By Me," for example. I find it hard to believe any human could watch that movie without getting wistful for the journey that is adolescence.)

I looked far and wide to find another expert who so directly described nostalgia as a yearning for a specific past emotion more than a specific past event, but I came up short. So I shied away from focusing on that definition here. But just so you know, it's out there.

Routledge, Clay. "The Rehabilitation of an Old Emotion: The New Science of Nostalgia." Scientific American. July 13, 2013. (April 22, 2015) http://blogs.scientificamerican.com/mind-guest-blog/2013/07/10/the-rehabilitation-of-an-old-emotion-a-new-science-of-nostalgia/

Tierney, John. "What is Nostalgia Good For? Quite a Bit, Research Shows." The New York Times. July 8, 2013. (April 21, 2015) http://www.nytimes.com/2013/07/09/science/what-is-nostalgia-good-for-quite-a-bit-research-shows.html?pagewanted=all&_r=1

University of Chicago Press Journals. "The nostalgia effect: Do consumers spend more when thinking about the past?" July 22, 2014. (April 30, 2015) http://www.eurekalert.org/pub_releases/2014-07/uocp-tne072214.php

University of Southampton. "Nostalgia: What Nostalgia Is and What It Does." (April 23, 2015) http://www.southampton.ac.uk/nostalgia/what_is_nostalgia/